1. Field of the Invention
The present invention relates to a device which handles AV (audio/video) contents, and in particular, to a reproducing device, a reproducing method, and a receiving device, which are provided with content protection technology such as an HDD recorder, an STB (set top box) having a built-in HDD, a personal computer, or the like.
2. Description of the Related Art
In recent years, devices, which record in a built-in hard disk drive (hereinafter, referred to as HDD), contents (programs consisting of images/sound, programs by digital broadcasting, data by data broadcasting, and the like) sent by broadcasting, and which enable a program which has already been recorded in the HDD to be watched and listened to while recording a program which is currently being broadcast, and DVD recording/reproducing devices or VTRs which have a built-in HDD, have started to be sold by respective companies.
Various demands have been made on such devices by copyright holders, and currently, discussions are being carried out between the parties which transmit contents and the copyright holders. Specifically, content data which is broadcast by digital broadcasting does not deteriorate even if copied. Thus, the standardization of processing by which data is recorded in an HDD which is built in a device, and after ninety minutes, for example, have passed, the recorded data is automatically erased, and the standardization of MOVE processing in which immediately after data is reproduction-outputted from the built-in HDD, the data (the original data) which is still recorded in the HDD and which corresponds to the reproduction-outputted data is erased, and the like, have advanced.
A case where MOVE processing of a content from an HDD to a DVD-RAM is carried out, in a conventional DVD recording/reproducing device in which an HDD is built (hereinafter called HDD built-in DVD device), will be described hereinafter.
First, a signal including content transmitted from a broadcasting station is processed by a tuner and/or a decoder, and thereafter, is inputted to the HDD built-in DVD device, and is entirely stored once in the HDD which is built in the device.
When a user wishes to record onto a DVD-RAM the aforementioned content recorded once in the HDD, a control device in the HDD built-in DVD device instructs the HDD to reproduce the content, and instructs a DVD drive to record the content which is reproduced. Then, in the HDD built-in DVD device, the designated content is recorded onto a DVD-RAM disk via an IDE interface or the like from the HDD.
At this time, when the content is a content having a restriction on copying, i.e., is a content such that the original data in the HDD must be erased if the data is reproduced one time, immediately after the data is reproduction-outputted for recording onto the DVD-RAM disk, the data which is still recorded in the HDD and which corresponds to the reproduction-outputted data is erased from the HDD. In this way, a processing which erases the recorded content of the source of reproduction at substantially the same time as reproduction-outputting is called MOVE processing. Note that, when data is recorded onto a DVD-RAM, the content is set as copy prohibited data (“No more copy” data), and further copying thereof is prohibited.
Next, operation in a case where a set top box which has an HDD built-in (hereinafter referred to as an HDD built-in STB) carries out MOVE processing of a content from the HDD to a digital TV (display) connected to the STB will be described.
First, a signal including content transmitted from a broadcasting station is received and processed by a digital broadcast receiving section of the HDD built-in STB, and thereafter, is entirely stored once in the HDD built in the device. The content inputted to the HDD built-in STB may be, other than a signal received by the digital broadcast receiving section, a signal reproduced by another reproducing device such as a DVHS or the like.
When the user wishes to, by using a digital TV, reproduce, watch and listen to the content which has been entirely recorded once in the HDD, the user instructs the HDD built-in STB to reproduce the content. The control device in the HDD built-in STB instructs the HDD to reproduce the content. Then, the content is reproduced from the HDD, and is outputted to the digital TV via an IDE interface or an IEEE 1394 interface. The content is thereby reproduced, watched and listened to on the digital TV.
At this time, when the content must be erased if reproduced one time, the content which has been recorded in the HDD, whose data has been reproduction-outputted, is erased from the HDD at the time of being reproduction-outputted from the HDD onto the digital TV for watching and listening.
In this case, when the content is reproduced while being recorded, if the user sets the reproduction state into a pause state and leaves his/her seat and then returns thereafter for example, the user can continuously watch and listen to the program from the scene at the time when the user left his/her seat.
In this way, when the content received is not reproduction-outputted for long-term storage and is reproduction-outputted for viewing and listening to on a digital TV or the like, the reproduction-outputted data is erased from the HDD. This processing is included in MOVE processing.
When data recorded in the HDD is erased at the time of MOVE operation, the reproduction-outputted data may be actually erased by an erase head. Or, the address values of the respective data recorded in a management table in the HDD which manages the positions of recorded data may be erased such that the data cannot in any way be correctly reproduced from the HDD.
Further, when data recorded in the HDD is erased at the time of MOVE operation, the respective data which form the content are erased immediately after reproduction-outputting (copying), or are erased after a certain time has passed after reproduction-outputting. When the content recorded in the HDD is erased after reproduction-outputting an entire content, a state arises in which the same contents exist on recording media such as the HDD, the DVD-RAM and the like. This is therefore unfavorable from the standpoint of copyrights.
In such MOVE processing, no consideration whatsoever has been given in the prior art to a power being turned off in the midst of MOVE such that the processing is interrupted.
In this way, in conventional reproducing devices, reproducing methods and receiving devices, MOVE does not erase the original content after the content has been entirely reproduced (or copied). For example, each time a data packet is reproduced, MOVE erases the corresponding data packet in the HDD.
There may be cases where, in the midst of MOVE operation, MOVE operation is interrupted due to the power switch of the device being turned off, or due to power off being instructed by the user misoperating the remote controller, or due to a power off command being inputted from another device via a network such as IEEE1394. In such a case, because a part of the original stream has already been erased, there is the problem that the content which has been subjected to MOVE processing cannot be restored at either of the transmitting side or the receiving side, and a part or all of the content cannot be reproduced.
There is an OS which utilizes, as a technique of moving files in a personal computer, a method in which, in order to protect a file, the entire file is copied once, and the copy is verified with the original file, and after confirming the correspondence, the original file is erased. In the case of such an OS, because the backing-up itself can be thought of as a complete copy, in the case of AV content which is copyrighted, this is not permissible from the standpoint of the intent of the copyright holders.
As described above, if a power off request arises at a device at which MOVE operation is being carried out, and the power of the device is turned off and operation is interrupted, there is a problem in that the original stream cannot be restored and a part of or all of the content cannot be reproduced.